Over the years, Ethernet has become the most commonly used method for local area networking. The IEEE 802.3 group, the originator of the Ethernet standard, has developed an extension to the standard, known as IEEE 802.3af, that defines supplying power over Ethernet cabling. The IEEE 802.3af standard defines a Power over Ethernet (PoE) system that involves delivering power over unshielded twisted-pair wiring from a Power Sourcing Equipment (PSE) to a Powered Device (PD) located at opposite sides of a link. Traditionally, network devices such as IP phones, wireless LAN access points, personal computers and Web cameras have required two connections: one to a LAN and another to a power supply system. The PoE system eliminates the need for additional outlets and wiring to supply power to network devices. Instead, power is supplied over Ethernet cabling used for data transmission.
As defined in the IEEE 802.3af standard, PSE and PD are non-data entities allowing network devices to supply and draw power using the same generic cabling as is used for data transmission. A PSE is the equipment electrically specified at the point of the physical connection to the cabling, that provides the power to a link. A PSE is typically associated with an Ethernet switch, router, hub or other network switching equipment or midspan device.
PD is a device that is either drawing power or requesting power. Among examples of PDs are such devices as digital IP telephones, wireless network access points, PDA or notebook computer docking stations, cell phone chargers, HVAC thermostats, factory automation equipment, ID scanners, security systems, credit card terminals, and keyless entry systems.
PSE searches the link for a PD requesting power, optionally classifies the PD, supplies power to the link if a PD is detected, monitors the power on the link, and disconnects power when it is no longer requested or required. PD participates in the PD detection procedure by presenting a PoE detection signature defined by the IEEE 802.3af standard. If the detection signature is valid, the PD has an option of presenting a classification signature to the PSE to indicate how much power it will draw when powered up. Based on the determined class of the PD, the PSE applies the required power to the PD.
Since PD may be a small portable device, it would be desirable to decrease size of an arrangement required to support PoE procedures on the PD side. Therefore, there is a need for a compact integrated PD connector that would perform all functions required to support connection of PD to an Ethernet link.